It is becoming more common to use lasers to perform various surgical procedures, research functions, industrial processes, and similar techniques. It is well-known that the radiation from such lasers must be confined to the operative area, and that the lasers used under a variety of circumstances pose a danger to personnel and equipment. It is equally well-known that it is difficult, if not at times impossible, to prevent the occurrence of stray radiation in such situations.
In particular, surgical operating room personnel have begun wearing protective eyeglasses, and patients undergoing laser operative procedures have been provided moistened gauze over the eyes. More recently, a surgical eye mask has been developed to protect patients during laser surgery. (See U.S. Pat. No. 4,635,625.) Surgical shields or blankets have also been developed to protect operating room patients, personnel and equipment. (See U.S. Pat. Nos. 4,616,641 and 4,715,366.) A laser-resistant backup pad (U.S. Pat. No. 4,520,814), and a ceramic dish (West German Patent No. 2,207,387) have also been developed to protect operating room patients during laser surgery.
The need for detection of the presence of errant or stray radiation, as well as a means to prevent harm to personnel and equipment during laser-use operations without surgery degrading the efficiency of the operating environment has become apparent. Importantly, personnel utilizing lasers need a means to quickly and effectively alert them of the presence of stray radiant energy that may injure personnel and equipment in their work environments. Further, under the intense, bright ambient lighting conditions that must exist in surgical operating rooms, it is difficult to detect the presence of stray radiation unless that radiation results in pain or is otherwise noticed by a conscious occupant of the operating room when existing shields that may or may not provide adequate protection are used. Present day eye, personnel and equipment shields are comprised of a highly reflective, aluminized, albeit matte, surface or finish. These shields may in many situations degrade the efficiency of the laser operating environment by reflecting ambient light into the eyes of the personnel working in that environment.
Personnel may be injured by direct exposure to a laser beam on the skin, causing burns or flesh wounds, or, in some situations, opthalmic injury or loss of vision can result if the eyes were to become accidentally exposed. In particular, operating room patients are highly at risk when anesthetized, particularly when a patient is under general anesthesia), since the patient is unaware of or otherwise unable to alert the surgical personnel of the occurrence of an injury or dangerous condition.
The use of wet towels to protect against stray laser energy is not a satisfactory method because the sterile plastic sheet below the towels can be ignited by the laser beam. Furthermore, bacterial contamination may occur when plastic sheets are not used to protect the patient. There is a potential of fire from towels which have not been remoistened during the operative procedure. As such, wet towels and other similar methods in no way served to effectively warn personnel of the presence of stray laser radiation until after injury may have occurred.
The potential laser hazards encountered by patients are also encountered by the operating room personnel. Although operating room personnel can, to some extent, avoid continued contact from the beam by stepping out of its path or by alerting the user, it is not always possible for personnel to be aware of and to then remove themselves from the path of the laser beam. In many cases, it is difficult to identify a potentially dangerous stray laser radiation problem until after injury has occurred. Even short exposures may cause injury, provided operating personnel discover in time that a dangerous stray laser radiation condition exists.
Another problem encountered is the exposure of the operating room equipment such as anesthesia machines and circuits to undetected laser radiation. Anesthesia circuits often must be positioned near the operative field, especially during neurosurgery or during facial or oral surgery. Typically, these circuits have been wrapped in aluminum foil to deflect the stray radiation. However, such wrapping prevents the anesthesiologist from observing these circuits Aluminum foil is very difficult to work with, especially around the endotracheal tube, and often fails to provide sufficient protection to equipment.
Another problem encountered with other laser shields is the undesirable conditions that these reflective shields, drapes and eye masks create in the operating room due to their tendency to reflect the high-intensity lights in operating rooms so as to distract and otherwise impair the vision of operating room personnel. A need for a laser warning and protective system that becomes effective only once an actual dangerous stray laser radiation condition is present in the operating room has become apparent. The highly reflective surface of present day shields, although needed to protect against the harms caused by stray radiation once that radiation is actually encountered, has the effect of lowering the efficiency of laser operating personnel whose vision is impaired by the very qualities that make such shields effective against laser radiation.
The same problems that occur in surgical laser applications may also occur when lasers are used for research, industrial, and a variety of other purposes; personnel can risk serious injury and equipment may be damaged when errant laser radiation remains undetected or unprotected against.
It would be desirable, therefore, to provide a laser-shield warning system alerting personnel who utilize lasers by visual, audible and odor or vapor alarm means of the presence of stray laser radiation and which records the path and presence of that radiation, and at the same time protects patients, personnel, and equipment from damage caused by lasers. It is also an objective of the present invention to improve the ability of laser shields to thermally insulate personnel and equipment against undesired exposure to laser energy using even more compact and lightweight, yet highly protective laser shields. It is a also an objective of the invention to provide a laser shield that does not reflect the intense ambient light of the operating room/laser use facility so as to distract or impair the vision of laser operators in the performance of their tasks.